280AI & 160gr Partitions issues

[Twraska]

Haven’t been here long, but it seems most of y’all go for practical over fancy and latest gadgets. So, with that said, I’m trying to get a load for my daughter in her Weatherby Camilla (ladies) that she can hunt whitetail and nilgai with the same load. The gun has a 9” twist, 24” barrel and a 2” factory muzzle break. Right now she is probable comfortable taking up to 300 yard shot and hopefully with some trigger time on this gun, that actually fits her 5’ frame, she will stretch that out to 400+, especially on the nilgai.

So now for my dilemma. Straight out the box my son and his buddy loaded some 140gr cup and core loads. Play with the new gun loads! IDK what they were, just the cheapest box on the shelf with a middle of the road powder charge as listed in the manual. The thing was sighted in and shot an honest 1” group at 100 yards.

So, they went and loaded three different powders (what they had on the bench but I think it was H1000, 4350 and 4831) at three different charge weights pushing 160gr Partitions and about the best they could do was a 2” or so group. Nothing seemed to work. (The cup and core bullets are generally not recommended for nilgai, but she has a bull on the wall taken with a 90 grain out a 25-06 at 200 yards.)

My questions…..
Are Partitions that bad of accuracy at 100 yards?
Is the twist fast enough? Too fast?
Too heavy a bullet?
Would a bonded bullet (Accubond, Sirocco) be a better choice?
Try a 150gr? I don’t think they make it in a Partition, 140 & 160 only.
Try to conjure up some A-frames?
Is a TTSX or other monolithic a better choice?

All replies are welcome!
Thanks
Tim

 

[HuntingGold]

I'm doing 0.6 inches with 160 grain Partitions and I'm not done with my tinkering. Those are being shot out of my Christensen Arms rifle with 1 in 9 twist. That was using Reloder 22. Since that will no longer be available, I've been tinkering with H4831SC. I've had too many projects and have not narrowed down my final load yet, but the tests looked acceptable.

Maybe your particular gun doesn't like Partitions? Unfortunate, as Nathan Foster out of New Zealand has high praise for them in that weight class. I think his website is ballistic studies or similar.

 

[Nevada Mike]

I have a couple boxes of 7mm 150 grain Partitions, so I know that they have made them in the past at least. Nosler currently lists 7mm NP in 140, 150, 160, and 175 in Nosler #9 manual.

In my 280AI (224" 8.5:1" twist) I'm using H4831sc and VV N560. Best results so far have been 140 accubond with 61 to 62.5 gr. N560 @ 3100 fps and 0.75" tp 0.52" groups. Still playing with this.

 

[shootist~]

Barnes TTSX or LRX all the way for a Nilgai bull, per my outfitter (the property's hunting manager) and guide (a local game warden). Also me - per my sample of one (soon to be two I hope).

Guide's wife took her Nilgai with a 127 gr Barnes LRX, 6.5 PRC.

As I'm sure you know, cup and core works just fine for whitetail, but is less than ideal for Nilgai.

Edit to add: Possibly @dchum who guides for Nilgai, will chime in with a recommendation for the 280 AI.

 

[Russ16]

Sometimes a gun just doesn’t like a bullet.

I would give the Barnes TTSX a try. Then maybe Accubond and A frames if they are available. Also different powder charges of course. I have one rifle that groups can double in size with a half grain difference in powder.

Were the cup and core and partitions loaded with the same jump to the lands?

 

[CO_mtnman]

I just completed a work up for my brother's 280 ackley, I tried the 160 gr nosler partition, 160 gr nosler accubond and 150 gr barnes ttsx all with h4831sc powder. His rifle did not shoot the partitions very good they averaged about 1.1" across all powder changes, his rifle shot the accubonds with a average of .7" and the ttsx bullets with a average of .6". I wouldn't worry if your rifle won't shoot the partitions there are many other good bullet choices out there, listen to what your rifle is telling you

 

[Twraska]

Barnes TTSX or LRX all the way for a Nilgai bull, per my outfitter (the property's hunting manager) and guide (a local game warden). Also me - per my sample of one (soon to be two I hope).

Guide's wife took her Nilgai with a 127 gr Barnes LRX, 6.5 PRC.

As I'm sure you know, cup and core works just fine for whitetail, but is less than ideal for Nilgai.

Edit to add: Possibly @dchum who guides for Nilgai, will chime in with a recommendation for the 280 AI.

Thanks for the reply. However, I’m needing a single load for both. I don’t think I made that clear in my OP.

Her hunting opportunities may allow cull whitetail bucks, trophy whitetail or nilgai at any given time during the day at ranges as close as 30 yards on the deer, 50-75 on the nilgai and as long as she feels comfortable taking a shot. I know that’s asking a lot out of a single round, but that’s the reality of the hunt.

 

[dchum]

No, partitions can be just as accurate as any bullet at 100 yards.

I would try a 140ttsx or a 150ttsx, either would be great for deer and Nilgai. even better for Nilgai imo.
If I was going to use a 7mm for Nilgai I would really want it to be loaded with a Monolithic bullet.

I feel your issues too, I hunt where deer and Nilgai roam, I much prefer partition, SST, or cheap ammo for deer. Just kills faster than monos. But I just stick with the Barnes because of Nilgai and hogs. Now if I’m hunting deer not in Nilgai country I’m using “non premium” because it kills deer faster (just from my observation)

 

[RedTag]

I think we must maintain realistic expectations when it comes to shooting larger game at longer distances with small bore rifles. The Barnes bullet in particular needs high impact velocity to initiate expansion correctly. This works great at 100 or 200 yards. But at 300 or 400 maybe not so much. I have struggled with accuracy of lead-free bullets in several rifles too. I think you’re on the right track with the Nosler partition as it’s arguably the most versatile option in this weight class. I would try to find a box of factory loaded partition ammo if possible and see how the rifle does with it; and if successful then work on the hand loads from there.

 

[Luvthunt]

Bought my first Rem. 7mm mag back in the 60s. I believe I used Nosler 160 part. exclusively and they grouped around 1 Moa

 

[112Savage]

Try 160 Accubond. The 160 ballistic tip could be the whitetail bullet. They have the same profile, so should shoot similarly

 

[dchum]

I think we must maintain realistic expectations when it comes to shooting larger game at longer distances with small bore rifles. The Barnes bullet in particular needs high impact velocity to initiate expansion correctly. This works great at 100 or 200 yards. But at 300 or 400 maybe not so much. I have struggled with accuracy of lead-free bullets in several rifles too. I think you’re on the right track with the Nosler partition as it’s arguably the most versatile option in this weight class. I would try to find a box of factory loaded partition ammo if possible and see how the rifle does with it; and if successful then work on the hand loads from there.

A 140 TTSX from a 280 AI will absolutely kill at 400 yards. Especially on a dense medium like the Nilgai.

Not sure what you are on about, do you have much killing experience with mono metals or are you saying what you maybe had heard?

If he’s having accuracy issues with the partition than he should absolutely try TTSX (a better Nilgai bullet even at 400 yards)

 

[Twraska]

A 140 TTSX from a 280 AI will absolutely kill at 400 yards. Especially on a dense medium like the Nilgai.

Not sure what you are on about, do you have much killing experience with mono metals or are you saying what you maybe had heard?

If he’s having accuracy issues with the partition than he should absolutely try TTSX (a better Nilgai bullet even at 400 yards)

Thanks for your input. Do you have experience with the TTSX on whitetail deer at any yardage from 25 on up?

 

[Twraska]

Try 160 Accubond. The 160 ballistic tip could be the whitetail bullet. They have the same profile, so should shoot similarly

Thank you for your reply. I am trying to find one bullet for both whitetail and nilgai as you never know what opportunity will present itself, and you will not have time to kick out a cartridge and reload.

 

[dchum]

Thanks for your input. Do you have experience with the TTSX on whitetail deer at any yardage from 25 on up?

Yes it works fine. I’ve just noticed sometimes on a classic “well behind the shoulder” shot on a WT they may run a little further than with a say soft round.

But for all other angles they kill really well. And I think it’s a fair trade off to use Barnes. Just my dumb opinion.

Here is a 168 gr Barnes TTSX going slow out of an old 30-06. Shot was about 130 yards. (Younger cull buck on a highly managed MLD ranch. So shooting younger bucks was the plan)

Ask you can see the Barnes kills him well - punching the front shoulder on a quartering too shot.

I camp gun where I worked at one point was a 300 win with cases of Barnes 180 ttsx to feed it. That was very decisive on Texas whitetail to say the least…

I think you would find them adequate out of your 280 for deer

Best

 

[longrangehunterII]

My first accurate rifle was a 280 AI built by Kenny Jarrett over twenty years ago. It came with two loads that shot 1/2” groups with not much help from me. They were both Nosler’s, a 150 BT behind IMR 4831, and a 175 Partition using IMR 7828. I killed everything with that rifle and used the BT in the chamber and the Partitions in the magazine.

I have a feeling that your Wby. has a pencil thin barrel, and on the long side? Which means it’ll take a bit of load development to make it shoot, or with a bit of luck come easy.

BTW, back in the day Kenny never liked the Barnes X bullets, now the Tipped TSX’s are among his favorite to use in his guns.

My current GAP Built 280 AI has a 26” M24/40 carbon Bartlein with a 1:8.7 twist vs the #4 24” on my older Jarrett Rifle which was either a 1:9 or 1:10”? Back when Hornady came out with their ELD’s I never could get them to shoot either.

I did however use a completely new reamer on my Terminus build designed by Dave Manson and a gentleman from NZ Nathan Foster. It came about to help with ease of making just about anything work in these guns and the newer higher BC bullets.

As much as I’d like to say that’s the case just like my older Jarrett the FMR 280 AI did not like any of the LRAB’s, ELD’s, etc. in my experience the NAB tends to take a bit more work than any Ballistic Tip, or Partition IMO. But I have gotten good accuracy with TSX FB bullets out of my older rifle.

Bonded bullets tend to take more effort to shoot vs how easy it is to get a BT, or NPT. Over the last twenty five years I tended to get them to shoot in roughly 25 rounds or less! They typically shoot well at around.020” to .030” off the lands.

I ended up with getting both the 160 BT’s and the 160 NPT’s to shoot to the same POI using the same load, 57.0 H4831sc. H4831sc was also used in my Jarrett with the Barnes TSX FB 160.

I might add that I don’t push them like Kenny loved doing and stuck with the velocity from the Hodgdon manual.

Good luck with your project and don’t be afraid to switch to a different bullet! The barrel will like what you’re using or not, best to just move on.

 

[FlyGuy]

With the right powder, Partitions are extremely accurate.
They like a bit of jump, so I would test a few more powders at the OAL in the Nosler manual.

 

[112Savage]

I bought some 145 LRX to try in my 280AI. I cleaned my barrel first but found a screaming and accurate load with RL23. I haven’t killed a deer yet but it goes through 7 jugs of water easily at 110yds and is accurate at 600 as well

WBY backcountry guide 1-9” twist

 

[shootist~]

Thanks for the reply. However, I’m needing a single load for both. I don’t think I made that clear in my OP.

@Twraska

No you were pretty clear on that point.

The general consensus on this forum, I believe, is to always load for the bigger tougher animal and use that same load for the smaller ones.

As Nathan Foster has mentioned on his site, you may want to break bones [on lighter game] to get better expansion and faster killing.

Trophy Bonded Tiped, the modern version of the excellent TTBC - also known as Federal Terminal Ascent, is another one to consider, although it's probably only available in factory loaded ammo:

Thread 'Any love for the federal terminal ascent?' https://www.africahunting.com/threads/any-love-for-the-federal-terminal-ascent.90950/

And finally - If your daughter is uncomfortable shooting 300+ yards under field conditions, tell her she has lots of company - and is a very wise young lady.

 

[Scott CWO]

Accubond. Nuff said.